This is one of the largest natural harbours in the world – and it’s also one of the safest. The harbour’s sheltered waters have always been a great place to learn to sail. Tucked away in a quiet corner of the harbour, near East Ferry, sailing instructor Eddie English is teaching Ireland’s next generation of mariners.

A few miles away, at Ringaskiddy, there’s a more high-tech training process at work. This is the new National Maritime College of Ireland which is equipping Ireland’s future ships captains and merchant seamen with the skills necessary to survive on the world’s oceans.

A few years from now, graduates of the Maritime College could find themselves coming into port on board a merchant vessel. The Port of Cork has responsibility for all maritime activity in the harbour and in the past five years the movement of ships has tripled. This is the harbour’s beating commercial heart, concentrated in Tivoli Docks and Ringaskiddy, but with some activity still reaching up into the old docks area in the city. The programme looks at the major contribution made by the Port of Cork to the economy of the south, south-west and west of Ireland.

The Port of Cork has been instrumental in bringing back to the harbour a sense of the old glory days, with the return of major cruise liners. In 2005, some 30 liners visited the port, bringing significant business to the region as a result.

The shelter offered by the harbour has made it a place of refuge for generations of seafarers. And when the call has gone out for rescuers, it has always been answered.

The sinking of the Lusitania in 1915 left 1,200 dead, but many were saved as the people of Cobh launched a dramatic rescue attempt in a flotilla of small boats to the site of the disaster, some 15 miles away. Hundreds of victims were buried in mass graves in the old cemetery outside the town.

Just a few generations ago, Cobh symbolised Ireland’s failure, as hundreds of thousands emigrated from its quays. Today, the story of that mass departure is told by the Cobh Heritage Centre, which provides a multi-media insight into how 2.5 million people left this quayside for life in another land.

Of the hundreds of thousands of souls who passed through this place, one young girl was plucked out for a place in history. Annie Moore left the harbour with her two brothers on Dec 20, 1891. After 12 days in steerage, she arrived in New York on New Year’s Day 1892, and became the first emigrant to be processed through Ellis Island.

But for most emigrants, Cobh never existed. It was called Queenstown, and local historian Michael Martin explains how the name changed.

As the emigrant ships left the harbour over the centuries, one area of Cobh was burned into popular memory - the Holy Ground. The emigrant’s last sight of the town, it was also an area of some repute for visiting sailors.

Over the years, the passage of ships in and out of the harbour has sometimes had unexpected spin-offs for its inhabitants. The Celtic went aground at Roches Point in 1928, but pieces from her cabins still find pride of place in many harbour homes. Even the doors from her dining room have ended up in one of Cork city’s most famous pubs.

Out at Roches Point, there’s a real sense of the harbour’s place at the edge of the cold Atlantic. But this is a massive body of water, and the scene becomes decidedly more tropical as you move further into its heart. The programme ends with a trip to Fota Wildlife Park, and a close-up with one of its residents.